CN110603862B - Method and apparatus for reporting power headroom - Google Patents

Abstract

A method of reporting a power headroom and an apparatus using the same are provided. The apparatus calculates and reports a power headroom of a Physical Uplink Shared Channel (PUSCH) transmitted in a first transmission period of a first frequency band having a first subcarrier spacing. The power headroom is calculated based on at least one second transmission interval of a second frequency band having a second subcarrier spacing overlapping the first transmission interval.

Description

Method and apparatus for reporting power headroom

Technical Field

The present disclosure relates to wireless communication, and more particularly, to a method of reporting a power headroom in a wireless communication system and an apparatus using the same.

Background

In the third generation partnership project (3GPP), the seminar held 9/2015 agreed on the overall timetables and concepts of the 5G standardization. Enhanced mobile broadband (eMBB), large-scale machine type communication, ultra-reliable and low-latency communication (URLLC), etc. have been defined as top-level use cases. To meet service scenarios and new requirements, 3GPP has determined to define a New Radio (NR) that is different from the existing Long Term Evolution (LTE), and has defined both LTE and NR as 5G radio access technologies.

Uplink Transmit (TX) power is controlled to reduce battery consumption of the terminals and mitigate interference due to uplink transmissions between the terminals. With the introduction of terminals and base stations supporting more flexible bandwidth and channel structure, there is a need to efficiently control uplink TX power.

Disclosure of Invention

Technical problem

The present disclosure provides a method for reporting a power headroom and an apparatus using the same.

In one aspect, a method for reporting power headroom in a wireless communication system includes calculating a power headroom of a Physical Uplink Shared Channel (PUSCH) transmitted in a first transmission period of a first frequency band having a first subcarrier spacing; and reporting the power headroom. The power headroom is calculated based on at least one second transmission period of a second frequency band having a second subcarrier spacing, the at least one second transmission period overlapping the first transmission period.

In another aspect, an apparatus for reporting power headroom in a wireless communication system includes a transceiver configured to transmit and receive radio signals; and a processor operatively coupled to the transceiver. The processor is configured to calculate a power headroom of a Physical Uplink Shared Channel (PUSCH) transmitted in a first transmission period of a first frequency band having a first subcarrier spacing, and report the power headroom via the transceiver. The power headroom is calculated based on at least one second transmission period of a second frequency band having a second subcarrier spacing, the at least one second transmission period overlapping the first transmission period.

Battery consumption of the device may be reduced and interference caused by uplink transmissions may be mitigated.

Drawings

Fig. 1 illustrates an example of a subframe structure to which the present disclosure is applied.

Fig. 2 shows an example of hybrid beamforming.

Fig. 3 illustrates transmission of a sounding reference signal according to an embodiment of the present disclosure.

Fig. 4 illustrates a method of reporting power headroom according to an embodiment of the present disclosure.

Fig. 5 shows an example of simultaneous transmission of a Physical Uplink Shared Channel (PUSCH) and a plurality of Physical Uplink Control Channels (PUCCHs).

Fig. 6 shows another example of simultaneous transmission of PUSCH and multiple PUCCHs.

Fig. 7 shows an example of Power Headroom (PH) reporting at different Uplink (UL) scheduling timings.

Fig. 8 illustrates an example of PH calculation based on whether or not Timing Advance (TA) is applied between cells.

Fig. 9 illustrates a Transmit (TX) power control method according to an embodiment of the present disclosure.

Fig. 10 shows an example of UL channel scheduling with a delay field.

Fig. 11 shows an example of UL feedback with a delay field.

Fig. 12 illustrates a problem caused by using an existing Transmit Power Command (TPC).

Fig. 13 shows an example of the proposed group TPC Downlink Control Information (DCI).

Fig. 14 shows another example of a proposed group TPC DCI.

Fig. 15 shows another example of the proposed group TPC DCI.

Fig. 16 shows an example of timing applied after receiving the TPC DCI.

Fig. 17 is a block diagram illustrating a wireless communication system implementing an embodiment of the disclosure.

Detailed Description

A wireless device may be fixed or mobile and may be referred to by another term, e.g., User Equipment (UE), a Mobile Station (MS), a Mobile Terminal (MT), a User Terminal (UT), a Subscriber Station (SS), a Personal Digital Assistant (PDA), a wireless modem, a handheld device, etc. The wireless device may also be a device that only supports data communication, such as a Machine Type Communication (MTC) device.

A Base Station (BS) is generally a fixed station that communicates with the wireless devices and may be referred to by another terminology, such as an evolved node b (enb), a Base Transceiver System (BTS), an access point, etc.

Hereinafter, it is described to apply the present disclosure according to the third generation partnership project (3GPP) Long Term Evolution (LTE) based on 3GPP Technical Specifications (TS). However, this is for exemplary purposes only, and thus, the present disclosure is also applicable to various wireless communication networks.

In 3GPP LTE, Downlink (DL) physical channels may include a Physical Downlink Control Channel (PDCCH), a Physical Control Format Indicator Channel (PCFICH), a physical hybrid ARQ indicator channel (PHICH), and a Physical Downlink Shared Channel (PDSCH). Uplink (UL) physical channels may include a Physical Uplink Control Channel (PUCCH) and a Physical Uplink Shared Channel (PUSCH). Control information transmitted through the PDCCH is referred to as Downlink Control Information (DCI). The DCI may include a resource allocation of a PDSCH (also referred to as a DL grant) or a resource allocation of a PUSCH (also referred to as a UL grant).

New Radios (NR), which are 5G radio access technologies, support various bandwidths and frequency bands to enable more flexible scheduling. Not only the frequency band below 6GHz but also the frequency band above 6GHz is supported. The supported bandwidth is up to 100MHz at 6GHz or below and up to 400MHz at 6GHz or above. In addition, unlike 3GPP LTE which fixes a subcarrier spacing of 15kHz, NR may support various subcarrier spacings of 15kHz, 30kHz, 60kHz, 120kHz, or 240 kHz.

Fig. 1 shows an example of a subframe structure to which the present disclosure is applied.

The subframe is a unit indicating a Transmission Time Interval (TTI), and indicates a transmission interval of 1ms, for example. A slot is a unit of scheduling. For example, one slot may include 14 Orthogonal Frequency Division Multiplexing (OFDM) symbols. When the subcarrier spacing is 15kHz, 14 OFDM symbols in one slot correspond to 1 ms. If the subcarrier spacing is 30kHz, the slot still includes 14 OFDM symbols, but the subframe includes 2 slots.

A slot is divided into at least three regions in the time domain. The DL control region is a region for transmitting a DL control channel. The UL control channel is a region for transmitting the UL control channel. The data region is a region for transmitting a DL data channel or an UL data channel. The number of OFDM symbols per region and their positions are for exemplary purposes only. For example, the UL control region may be arranged to the first OFDM symbol of the first slot or the first OFDM symbol of the second slot.

A switching period for switching from the transmission mode to the reception mode may be configured between the respective areas. For example, at least one OFDM symbol between the UL control region and the data region for DL data may be configured as a Guard Period (GP) to function as a switching period.

In one slot, DL transmission and UL transmission are sequentially performed. The wireless device may receive DL data in one slot and may also send a hybrid automatic repeat request (HARQ) ACK/NACK. Accordingly, even if the received DL data has an error, the time required to receive the retransmission data is reduced, thereby minimizing data transmission latency.

Fig. 2 shows an example of hybrid beamforming.

New Radios (NR) may also operate on frequency bands above 6 GHz. Since the wavelength becomes shorter at a high frequency band, more antenna elements can be mounted in the same area. For example, the wavelength at the frequency band of 30GHz is λ 1 cm. A total of 100 antenna elements may be mounted in a two-dimensional array of λ/2 spacing on a 5x 5 cm panel. An increase in the number of antenna elements may result in an increase in beamforming gain, an increase in coverage or an increase in throughput.

A transceiver unit (TXRU) arranged to each antenna element enables Transmit (TX) power and phase adjustment, and independent beamforming is possible for each frequency resource. However, when the TXRU is installed in all of about 100 antenna units, cost efficiency can be reduced. A method may be considered in which a plurality of antenna elements are mapped to one TXRU, and the beam direction is adjusted using an analog phase shifter. Since only one beam direction over the full frequency band is possible in this analog beamforming scheme, frequency selective beamforming cannot be performed.

Hybrid Beamforming (BF) that maps N TXRUs to M antenna elements may be considered by intermediate forms of digital BF and analog BF. Here, M > N. In this case, although there is a difference according to a method of connecting the TXRU and the antenna element, the number of beam directions that can be simultaneously transmitted is limited to be less than or equal to N. Analog BF of hybrid BF means that an operation of precoding (or combining) is performed in a Radio Frequency (RF) end.

In a hybrid BF having N TXRUs and M antenna elements, the digital BF of the L data layers to be transmitted may be represented by an N × L matrix. The converted N digital signals are converted into analog signals by N TXRUs, and then analog BF represented by an M × N matrix is applied. In this case, the number of digital beams may be L, and the number of analog beams may be N. Further, the NR system considers a design in which the BS can change the analog BF on a symbol basis to support more efficient BF for UEs located in a specific area. When defining N TXRUs and M antenna elements as one antenna board, the NR system also considers a method of introducing multiple antenna boards capable of applying independent hybrid BF.

As described above, the NR system supports flexible UL scheduling by allowing PUSCH and PUCCH transmissions configured with various numbers of symbols even in a default time unit. Analog BF is also applied to UL transmission to improve transmission efficiency through the optimal RX-TX beam pair. Since both a single-carrier frequency division multiplexing (SC-FDM) scheme and an OFDM scheme are supported in PUSCH transmission, UL waveforms having different peak-to-average power ratio (PAPR) characteristics can be selected according to the coverage of a wireless device. Both a waveform with a low PAPR and a waveform with a high PAPR but supporting a high transmission rate are also supported in PUCCH transmission.

Hereinafter, the following terms are used for convenience.

-UL beam pair: combination of UL TX beams transmitted by a wireless device and UL RX beams received by a BS

-SC-FDM PUSCH: SC-FDM is a scheme in which a set of modulation symbols is Discrete Fourier Transform (DFT) precoded and then Inverse Fast Fourier Transform (IFFT). It is a PUSCH transmitted in the form of a waveform with a low PAPR.

-OFDM PUSCH: and a PUSCH transmitted in a manner that modulation symbol sets are subjected to IFFT while DFT precoding is not performed.

-sequence PUCCH: a PUCCH transmitted in the form of one or more sequences having a low PAPR.

-OFDM PUCCH: a PUCCH transmitted in the form of performing IFFT on a modulation symbol set.

-L-PUCCH: a PUCCH transmitted through a relatively large number of OFDM symbols (e.g., 4 OFDM symbols or more) in one slot or transmitted between multiple slots.

-S-PUCCH: PUCCH transmitted through a relatively small number of OFDM symbols (e.g., 2 or less OFDM symbols).

The different PUCCH formats refer to PUCCH formats that are different by the number of symbols, bandwidth, modulation type (e.g., sequence PUCCH and OFDM PUCCH), channel coding scheme, and the like.

Now, a method of controlling UL power in various UL transmission environments is proposed.

Fig. 3 illustrates transmission of a sounding reference signal according to an embodiment of the present disclosure.

In step S310, the wireless device determines a UL beam pair for Sounding Reference Signal (SRS) transmission. In step S320, the wireless device determines the TX power of the SRS corresponding to the UL beam pair. In step S330, the wireless device transmits SRS according to the determined TX power.

The SRS may be used by the BS to measure UL channel quality for UL scheduling, or may be used for beam selection/optimization between the BS and the wireless device. When the wireless device transmits the SRS through different TX beams at different timings or transmits the SRS through the same TX beam at different timings, the BS applies different RX beams to each SRS transmission to measure the RX quality. The BS may select the best UL beam pair with which to communicate with the wireless device. For convenience, the SRS transmitted for each UL beam pair is referred to as bssrs.

The bssrs TX power can be optimized for each UL beam pair if appropriate UL power control is applied to each UL beam pair. However, complexity and signaling overhead for performing power control for each UL beam pair increases. For a particular UL beam pair, the BS may have to transmit bssrs when control is lost or before control is obtained. Even if power control is maintained for multiple UL beam pairs, in order to fairly compare link efficiencies of the multiple UL beam pairs, it may be effective to adjust the TX power of the bSRS to the same level with respect to each UL beam pair.

Therefore, the present embodiment proposes a scheme for UL power control of multiple UL beam pairs. Hereinafter, when it is referred to as "UL beam pair", both the RX beam of the BS and the TX beam of the wireless device may be considered, or only the TX beam of the wireless device may be considered while ignoring the RX beam of the BS. The bssrs corresponding to each UL beam pair transmitted by the wireless device may be divided by time, frequency, sequence, etc.

In the first embodiment, the TX power of the bSRS corresponding to the UL beam pair may be configured based on the TX power of the bSRS corresponding to the UL reference beam pair.

Let bssrs corresponding to the ith UL beam pair (referred to as UL BP (i)) be bssr (i). Here, i is 1. K may be the total number of all UL beam pairs that the wireless device may form. Alternatively, K may be the number of beam pairs in the set of beam pairs that the wireless device may form. The TX power of bsrs (i) may be configured based on the TX power of bsrs (j). Here, 1 ═ j ═ K. UL BP (j) denotes a UL reference beam pair. The UL reference beam pairs may apply to all UL beam pairs that may be formed by the wireless device. Alternatively, a UL reference beam pair may be applied to each UL beam-pair group formed by the wireless device.

The UL reference beam pair may be defined in the following manner.

(i) The BS notifies the wireless device of information on the UL reference beam pair through RRC signaling or the like.

(ii) When the BS triggers bSRS transmission for a plurality of UL beam pairs through DL Control Information (DCI), the DCI may include information on UL reference beam pairs.

(iii) An UL beam pair for a current (or most recent) UL transmission or the like among the plurality of UL beam pairs may be configured as an UL reference beam pair.

(iv) An UL beam pair of the smallest (or second smallest) bssr TX power among the plurality of UL beam pairs may be configured as an UL reference beam pair. As a criterion for selecting the smallest bSRS TX power, some elements for determining the final TX power of the bSRS may be used. As a criterion for selecting the smallest bssrs TX power, a fraction corresponding to the TX power accumulated by the closed loop power control command may be used.

(v) The UL beam pair of the largest (or second largest) bssr TX power of the plurality of UL beam pairs may be configured as an UL reference beam pair. As a criterion for selecting the maximum bSRS TX power, some elements for determining the final TX power of the bSRS may be used. As a criterion for selecting the maximum bssrs TX power, a fraction corresponding to the TX power accumulated by the closed loop power control command may be used.

In the above schemes (i) to (v), when it is said that the TX power of the bsrs (j) is configured based on the bsrs (j), it may mean that the TX power of the bsrs (j) is directly applied or a power offset is applied to the bsrs (j), or a power value accumulated by a closed-loop power control command is applied.

The TX power of bssrs (j) may be determined based on an average of the TX powers required for multiple UL beam pairs.

bssrs (j) may represent the TX power value required when SRS/PUSCH is transmitted for UL BP (j), or an offset of the TX power value.

In a second embodiment, the bssrs TX power corresponding to a beam pair may be configured based on the path loss corresponding to a particular DL beam.

In general, TX power to be applied to a physical channel of UL BP (i) may include a power component that compensates for UL path loss of UL BP (i). Since it is difficult for a wireless device to directly measure the UL path loss, the path loss value measured by the DL beam pair corresponding to the UL BP (i) can be regarded as the UL path loss. The path loss value of a DL beam pair may be obtained by measuring RX power by an RX beam for a DL reference signal different for each TX beam.

The UL path loss value for configuring the TX power of bssrs (i) may be determined based on the path loss values of the DL reference beam pair (or DL reference beams when the RX beam of the wireless device is not otherwise distinguished).

The DL reference beam pair may be different according to a time/frequency domain in which the DL reference signal is transmitted, and may be determined in the following manner.

(i) The BS notifies the wireless device of information on the DL reference beam pair through RRC signaling or the like.

(ii) When the BS triggers bSRS transmission for multiple UL beam pairs through DCI, the DCI may include information on DL reference beam pairs.

(iii) A DL beam pair corresponding to an UL beam pair for a current (or most recent) UL transmission or the like among the plurality of UL beam pairs may be configured as a DL reference beam pair.

(iv) A DL beam pair corresponding to an UL beam pair of the smallest (or second smallest) bssr TX power among the plurality of UL beam pairs may be configured as a DL reference beam pair.

(v) A DL beam pair corresponding to an UL beam pair of the maximum (or second largest) bssr TX power among the plurality of UL beam pairs may be configured as a DL reference beam pair.

In the above schemes (i) to (v), bsrs (i) may mean a TX power value required when the SRS or PUSCH of the jth beam pair is transmitted or an offset of the TX power value.

More specifically, the TX power of bssrs (i) corresponding to UL BP (i) at SRS transmission period q may be determined as follows. Here, the SRS transmission period may correspond to a slot or a subframe.

[ equation 1]

Here, P_CMAX(q) is the maximum TX power, P, configured to the wireless device in SRS transmission period q_offset(i) Is a parameter configured by higher layer signaling for UL BP (i), M_SRS(q) is the bandwidth allocated for SRS transmission in SRS transmission period q, α (i) is a parameter configured by higher layer signaling for UL BP (i), pl (i) is the DL path loss estimate (i) calculated by the wireless device for UL BP (i), h (q) is a parameter defined in SRS transmission period q. μ is a value that increases as the subcarrier spacing of the SRS increases. In the above equation, UL BP (i) may be referred to as a set of SRS resources defined for SRS transmission.

The UL beam pair may correspond to a relationship of UL transmission beams corresponding to DL RX beam directions, where the quality of the DL RX signals (e.g., SINR) is optimized. A TX beam may mean a TX spatial filter mode and an RX beam may mean an RX spatial filter mode. From the perspective of the wireless device, the different DL TX beams cannot be directly identified, but can be identified by different DL reference signal resources. The UL RX beam depends on the implementation of the BS and therefore may not be directly identifiable by the wireless device.

Fig. 4 illustrates a method of reporting power headroom according to an embodiment of the present disclosure.

The Power Headroom (PH) is used to provide information about the difference between the maximum TX power of the wireless device and the power estimated for UL transmission. The Power Headroom Report (PHR) may be periodically triggered or may be triggered by an instruction of the BS.

The following equation shows an example of the wireless device calculating PH in the transmission period q.

[ equation 2]

PH(q)＝P_CMAX(q)-{10log₁₀(M_PUSCH(q))+P_{O_PUSCH}(j)+α(j)PL+Δ_TF(q)+f(q)}

Here, P_CMAX(q) is the maximum configured TX power, M, configured to the wireless device in transmission period q_PUSCH(q) is the bandwidth allocated for PUSCH transmission in transmission period q, P_{O_PUSCH}(j) And α (j) is a parameter, PL (i) is a DL path loss estimate calculated by the wireless device, and Δ_TF(q) and f (q) are parameters.

In NR, UL channels with various waveforms may be transmitted, such as SC-FDM PUSCH, OFDM PUSCH, sequence PUCCH, OFDM PUCCH, and the like. When transmitting an UL channel having various waveforms, a wireless device can calculate a PH by assuming that a specific waveform is transmitted.

In the case where there are a plurality of waveforms that can be transmitted by the wireless device, the wireless device can calculate PH based on TX power assuming that a specific waveform is transmitted, regardless of the actually transmitted waveform. For example, even if the wireless device transmits SC-FDM PUSCH according to the scheduling of the BS orOFDM PUSCH, also by obtaining P assuming that the reference waveform is transmitted_CMAX(q) to calculate PH. The reference waveform may be an OFDM PUSCH having a relatively large PAPR characteristic and having a small PH range. Alternatively, the reference waveform may be an SC-FDM PUSCH with a larger PH range. The BS may provide information on a reference waveform, which is a criterion for calculating PH.

Similarly, even if the wireless device transmits the sequence PUCCH or the OFDM PUCCH according to the scheduling of the BS, the PH may be calculated assuming that the reference waveform is transmitted. The reference waveform may be an OFDM PUCCH having a relatively large PAPR characteristic and having a small PH range. Alternatively, the reference waveform may be a sequence PUSCH with a larger PH range. The BS may provide information on a reference waveform, which is a criterion for calculating PH.

Now, PH reporting for different UL beam pairs is proposed.

When UL transmission is performed through multiple UL beam pairs between the BS and the wireless device, the wireless device may report the PH of the PUSCH/PUCCH independently for each UL beam pair. When reporting PHs for any PUSCH transmission, the wireless device may report all PHs for the associated one or more UL beam pairs.

If the wireless device always reports PHs for multiple UL beam pairs, signaling overhead for PH reporting may increase. Thus, the wireless device may calculate the PH by assuming a designated UL reference beam pair of the plurality of UL beam pairs. The UL reference beam pair may be configured as follows.

(i) Configured by the BS through RRC signaling or DCI scheduling the PUSCH.

(ii) Designated as a UL beam pair used by the wireless device for PUSCH or PUCCH transmission.

(iii) The UL beam pair whose PH value is the (second) smallest value among the plurality of UL beam pairs. The wireless device may report the index of the corresponding UL beam pair to the BS.

(iv) The UL beam pair whose PH value is the (second) largest value among the plurality of UL beam pairs. The wireless device may report the index of the corresponding UL beam pair to the BS.

(v) The UL beam pair last transmitted (in the corresponding carrier or cell) by the wireless device or scheduled from the BS.

The wireless device may calculate and report the PH value while changing the UL reference beam pair according to the determined period or order.

It is assumed that the PH for the UL reference beam pair is a reference PH. The wireless device may report a difference between the reference PH and the PH for another UL beam pair.

The above scheme may be applied not only for the case where the wireless device transmits PUCCH or PUSCH in practice, but also for the case where the wireless device does not transmit PUCCH or PUSCH through any carrier or specific band part in the system band to perform PHR on the corresponding carrier or band part.

Now, a method for calculating PH when PUSCH is transmitted simultaneously with a plurality of PUCCHs in a transmission period is proposed.

In the conventional 3GPP LTE, PUSCH/PUCCH transmission is scheduled in units of subframes, and PH is calculated by assuming PUSCH/PUCCH transmission in one subframe. However, in NR, L-PUCCH and S-PUCCH are introduced, which may also be transmitted in units of slots or 2 to 3 OFDM symbols. Therefore, also in one subframe, the PUSCH and PUCCH may be transmitted in different OFDM symbols. Therefore, separate PHs need to be calculated.

Fig. 5 shows an example of simultaneous transmission of PUSCH and multiple PUCCHs.

The PUSCH is transmitted in one slot or one or more OFDM symbols. In addition, PUCCH1 and PUCCH2 are transmitted in different OFDM symbols in a slot. The wireless device may calculate and report the PH by using at least one of the following schemes.

(i) The PH is reported for each of all PUCCH transmissions that overlap with the PUSCH transmission. Which PUCCH format the PH belongs to may be reported together.

The PH1 is calculated by considering simultaneous transmission of PUSCH and PUCCH 1. The PH2 is calculated by considering simultaneous transmission of PUSCH and PUCCH 2. Here, both PH1 and PH2 were reported. For example, PH1 is calculated by considering simultaneous transmission of PUSCH and PUCCH1, and PH2 is calculated by considering PUSCH and PUCCH 2. The wireless device reports both PH1 and PH 2.

(ii) The minimum PH is reported in PUCCH transmission overlapping with PUSCH transmission. The PH may together report to which PUCCH format the PH belongs. For example, a smaller PH is reported between PH1 and PH 2.

(iii) The maximum PH is reported in PUCCH transmission overlapping with PUSCH transmission. Which PUCCH format the PH belongs to may be reported together.

(iv) The PH is reported based on a temporal first (or last) PUCCH transmission among PUCCH transmissions overlapping with a PUSCH transmission. Which PUCCH format the PH belongs to may be reported together. For example, greater PH is reported between PH1 and PH 2.

(v) Only PH irrespective of PUCCH transmission is reported.

(vi) The PH assuming transmission of a predetermined specific PUCCH format is reported.

Fig. 6 shows another example of simultaneous transmission of a PUSCH and multiple PUCCHs.

This is the case where PUCCH2 transmissions overlap with PUCCH1 transmissions in one or more OFDM symbols. The wireless device may calculate and report the PH by using at least one of the following schemes.

(i) The reporting takes into account the PH of all PUCCH transmissions that overlap with the PUSCH transmission. Which PUCCH format the PH belongs to may be reported together. For example, the wireless device calculates and reports one PH by considering PUSCH and PUCCH1/PUCCH 1.

(ii) The minimum PH is reported in PUCCH transmission overlapping with PUSCH transmission. Which PUCCH format the PH belongs to may be reported together.

(iii) The maximum PH is reported in PUCCH transmission overlapping with PUSCH transmission. Which PUCCH format the PH belongs to may be reported together.

(iv) Only PH irrespective of PUCCH transmission is reported.

(v) The PH assuming a predetermined specific PUCCH format is reported.

As in the embodiments of fig. 5 and 6, the PH may be reported according to the type of simultaneous transmission of the PUCCH and the PUSCH. However, alternatively, the slot may be divided into a plurality of symbol durations, and the PH may be reported for each symbol duration. Specifically, for example, a slot may be divided into a first symbol duration (e.g., 1 or 2 symbol PUCCHs) capable of transmitting an S-PUCCH and a second symbol duration (a PUCCH transmitted in more symbols than the S-PUCCH) capable of transmitting an L-PUCCH, and a PH may be reported in each symbol duration.

When PUSCH and PUCCH are transmitted through different OFDM symbols in the same slot, the wireless device can calculate and report PH by assuming that PUCCH and PUSCH are transmitted in the same OFDM symbol.

Fig. 7 shows an example of PH reporting at different UL scheduling timings.

Different subcarrier spacings or different slot lengths may be applied between cells (either between carriers or between frequency band portions). In this case, the UL scheduling timing may be different between the plurality of cells. Different UL scheduling timing between cells may result in ambiguous PH calculations.

For example, assume that cell 1 has a subcarrier spacing of 15kHz and cell 2 has a subcarrier spacing of 30 kHz. The OFDM symbol length of cell 1 is twice the OFDM symbol length of cell 2, and the subframe length of cell 1 is also twice the subframe length of cell 2, and after receiving the first UL scheduling in Subframe (SF) # n-3 of cell 1, the wireless device transmits the first PUSCH based on the first UL scheduling in SF # n of cell 1. Upon receiving the second UL scheduling in SF # m-3 of cell 2, the wireless device transmits a second PUSCH based on the second UL scheduling in SF # m of cell 2. When the wireless device calculates PH in SF # n of cell 1, it may be difficult to consider the second PUSCH transmission of cell 2. This is because the wireless device may have insufficient processing time for PH calculation when scheduling a new PUSCH transmission after SF # n-3.

Alternatively, even if UL slots between two carriers have the same length, it may be difficult to consider UL transmission to PH of one carrier through another carrier in a corresponding slot because scheduling timings of UL transmission of two carriers for the same slot are changed.

When the slot lengths are different from each other, this may mean that the number of OFDM symbols included in the slot varies. Because the time slots of the two cells are of different lengths, multiple time slots of one cell may overlap with one time slot of another cell.

Thus, a second PUSCH transmission scheduled after the time the first PUSCH is scheduled (or a time a certain time before the time the first PUSCH is transmitted) may not be considered for the PH calculation of the first PUSCH. Alternatively, the PH may be calculated by assuming that the second PUSCH transmission scheduled after the time when the first PUSCH is scheduled (or a time a certain time before the time when the first PUSCH is transmitted) is not the second PUSCH transmission scheduled in practice but a second PUSCH transmission of a predetermined format. For example, assume that the UL grant to PUSCH timing value configured in cell 1 for reporting the first PUSCH of the PH is 3 SFs. When calculating the PH of the first PUSCH transmitted in SF # n, the wireless device may ignore another PUSCH transmission scheduled after SF # n-3.

In addition, a case is proposed in which PH is calculated and reported by using at least one of the following schemes when a slot for transmitting a PUSCH including PHR overlaps with a plurality of slots of another cell due to a plurality of slot lengths therebetween (when SF # m and SF # m +1 of cell 2 overlap with SF # n of cell 1, and PHR is reported by a PUSCH transmitted in SF # n of cell 1 in the example of fig. 7).

(i) PH is calculated for multiple slots of cell 2, which overlaps with the slots (or subframes) of cell 1 for reporting PH.

(ii) The PH is calculated only for a slot in which a PUSCH (or another UL signal) is transmitted among a plurality of slots of the cell 2 overlapping with the slot of the cell 1 for reporting the PH.

(iii) The PH is calculated only for a slot in which a PUSCH (or another UL signal) is transmitted among slots of the cell 2 overlapping with a slot of the cell 1 for reporting the PH. For the remaining slots, only PHs considering the case where no signal is transmitted in cell 2 are calculated and reported.

(iv) PH is calculated only for a specific time slot (e.g., a first time slot, a last time slot, an initial second time slot, a second time slot from the end) among a plurality of time slots of the cell 2 overlapping with the time slot of the cell 1 for reporting PH.

(v) When the PH of the cell 2 is reported through the first PUSCH transmitted in the cell 1, the PH is calculated for a slot of the cell 2 overlapping with the nth OFDM symbol (e.g., n ═ 1) on which the first PUSCH of the cell 1 is transmitted. Alternatively, PH is calculated for the slot of cell 2, which overlaps the (n-r1) th OFDM symbol and the (n + r2) th OFDM symbol. Here, r1 and r2 are integers satisfying r1, and r2 > -0.

(vi) A plurality of schemes may be applied according to priorities among the schemes (i) to (v). For example, in the case where PUSCH is transmitted through a plurality of slots of cell 2 when scheme (ii) is applied, one slot may be selected from the plurality of slots by applying scheme (iv) and scheme (v).

The above scheme can also be applied to reporting not only the PH of the PUSCH transmitted in cell 2 but also the PH in the case of transmitting another physical channel such as PUCCH/SRS and the like.

The above-described scheme can be used to determine whether to report the PH of a specific physical channel transmitted through the cell 2, not only for the case where the transmission enable period for the physical channel of the cell 2 is divided into a plurality of periods in the slot period of the cell 1 due to different slot lengths between the cell 1 and the cell 2, but also for the case where a plurality of physical channels are transmitted through different symbols in one slot of the cell 2. That is, a plurality of slots of the cell 2 can be applied by replacing them with a plurality of physical channels transmitted in the cell 2.

Although the above scheme is described for cell 1 and cell 2, it can also be applied to PH calculation in carrier 1 and carrier 2 or band part 1 and band part 2.

Now, a PH report is proposed which takes into account Timing Advance (TA) between cells or carriers.

Fig. 8 illustrates an example of PH calculation based on whether TA is applied between cells.

If different TAs are applied to cell 1 and cell 2, the SF of cell 2 overlapping with the SF of cell 1 may vary depending on whether or not the TA is applied. As shown in fig. 8, the SF of the cell 2 overlapping with the SF # n of the cell 1 may vary depending on whether TA is applied. If TA is not applied to cell 2, SF # m and SF # m +1 of cell 2 overlap with SF # n of cell 1. When TA is applied to cell 2, SF # m +1 and SF # m +2 of cell 2 overlap with SF # n of cell 1 in a larger proportion than SF # m. In this case, the PH report will consider which SF may become ambiguous. Therefore, at least one of the following schemes may be applied.

(i) When SF boundaries (or slot boundaries) between different cells are not aligned, and when PH reported by SF # n of cell 1 considers UL transmission by cell 2, PH is calculated considering only transmission in SF overlapping at the maximum ratio among SFs of cell 2 overlapping with SF # n of cell 1.

(ii) When assuming a case where TA is not applied between different cells, the PH is calculated by considering transmissions in all overlapping SFs. In the example of fig. 8, the PH is calculated and reported by considering transmission of SF # n of cell 1 and SF # m +1 of cell 2.

(iii) When TA is applied between different cells, PH is calculated by considering transmission of SFs overlapping at a rate greater than a certain rate. In the example of fig. 8, the PH is calculated and reported by considering the transmission of SF # n of cell 1 and SF # m +2 of cell 2.

When PH is reported through a PUSCH transmitted at slot # n of cell 1, PH calculation based on the above-described embodiment of fig. 7 may be applied to a slot of cell 2, which overlaps with slot # n of the slot.

Now, a PH report based on semi-persistent scheduling (SPS) transmission in an unlicensed band is proposed.

The unlicensed band is a band in which various communication protocols coexist and shared use is guaranteed. The unlicensed frequency bands may include 2.5GHz and/or 5GHz frequency bands used by Wireless Local Area Networks (WLANs). A cell operating in the unlicensed frequency band is also referred to as an unlicensed cell or a Licensed Assisted Access (LAA) cell. An LAA cell is typically a secondary cell activated by a primary cell and is therefore also referred to as an LAA S cell. Basically, in the unlicensed band, it is assumed that the channel is secured by contention between the communication nodes. Therefore, communication in the unlicensed band performs channel sensing, and thus it is necessary to determine whether another communication node does not perform signal transmission. For convenience, this is called Listen Before Talk (LBT), and a case where it is determined that another communication node does not perform signal transmission is defined to confirm Clear Channel Assessment (CCA).

General PUSCH transmission is performed aperiodically according to dynamic scheduling of the BS. SPS transmission means that the wireless device periodically transmits PUSCH without additional signaling after reserving periodic time/frequency resources (referred to as SPS resources) for transmitting PUSCH. The wireless device transmits the PUSCH over SPS resources in the presence of UL data to be transmitted in an SPS transmission period. The wireless device does not perform PUSCH if there is no UL data to transmit in the SPS transmission period.

LBT is also applied to SPS transmissions in unlicensed cells. Therefore, even if the wireless device has UL data to be transmitted in the SPS transmission period, the PUSCH cannot be transmitted if another node occupies the wireless channel. In this case, it is assumed that the PUSCH to be transmitted through the corresponding SPS resource is an SPS PUSCH. In addition, it is assumed that cell 1 is a licensed cell operating in a licensed frequency band, and cell 2 is an unlicensed cell. When the PH is reported through the PUSCH transmitted in SF # n of cell 1, the SPS PUSCH may have to be considered together in SF # n of cell 2. Since whether to transmit the SPS PUSCH is determined according to the LBT result in SF # n of cell 2, it may be difficult to calculate the PH by considering PUSCH transmission in cell 1 and SPS PUSCH transmission of cell 2 together in SF # n. Therefore, the following scheme is proposed.

(i) The wireless device calculates the PH by assuming that the SPS PUSCH is not always transmitted, regardless of whether the SPS PUSCH of cell 2 is transmitted in practice.

(ii) The wireless device calculates the PH by assuming that the SPS PUSCH is always transmitted, regardless of whether the SPS PUSCH of cell 2 is transmitted.

(iii) The wireless device calculates the PH by assuming transmission of a PUSCH of a predetermined format regardless of whether the SPS PUSCH of cell 2 is transmitted. If available RB count/arrangement, Modulation and Coding Scheme (MCS), etc. are predetermined through SPS resources, the wireless device may calculate the PH by assuming corresponding parameters.

Meanwhile, the NR system may use an SC-FDM scheme or an OFDM scheme having a waveform for PUSCH transmission, which is referred to as an SC-FDM PUSCH or an OFDM PUSCH. In order to report multiple PHs for multiple waveforms, representative PHs and PH offsets are reported to reduce signaling overhead. In the presence of PH1 for SC-FDM PUSCH and PH2 for OFDM PUSCH, one of PH1 and PH2 may be selected as a representative PH, and a PH offset representing a difference between the selected PH and the remaining PHs may be calculated. Although there is no limitation in the criterion of selecting a representative PH, in practice, the PH of the transmitted waveform may be selected as the representative PH.

When the maximum TX power is reported for multiple waveforms, a representative maximum TX power and power offset for the selected waveform may also be reported. Maximum TX power means the maximum power that the wireless device can use when the UE transmits the corresponding waveform.

The PH offset (and/or power offset) may be reported with the representative PH value, or may be reported at a slower period than the representative PH value. The PH offset may be reported if the difference between the previously reported PH offset and the current PH offset is greater than a certain value. The PH offset may be reported when a certain time elapses after the last reporting of the PH offset. The PH offset may be reported if the MCS used in the PUSCH transmission differs by at least a certain level compared to the MCS used in the PUSCH reported previously. The wireless device may report the PH offset when establishing/reconfiguring RRC configuration required for PUSCH transmission.

Since the power backoff value required to transmit different waveforms is less affected by PUSCH scheduling, the wireless device may inform the BS of the power backoff value required to transmit different waveforms or the power backoff value between two waveforms. A reference environment (e.g., PUSCH bandwidth, PUSCH RB allocation, MCS, etc.) for calculating the power backoff offset value may be predetermined. The wireless device may report power backoff offset values for different reference environments.

OFDM PUSCH transmissions may have greater inter-cell interference or inter-cell interference than SC-FDM PUSCH transmissions. Thus, the value P configured to limit the maximum TX power of the wireless device may be configured independently for each waveform_CMAX. Value P of a waveform_CMAXCan be configured as the value P of another waveform_CMAXOf (3) is detected. P for SC-FDM PUSCH_CMAXP that can be configured to be larger than OFDM PUSCH_CMAX。

Different TX powers may be applied to the Reference Signal (RS) and UL data needed to adjust the target block error rate (BLER) according to the code rate or modulation order in the OFDM PUSCH transmission. In addition, when Uplink Control Information (UCI) and UL data are transmitted together on the PUSCH, the UCI and UL data may require different TX powers. In the first embodiment, the TX power difference between RS and UL data may be determined based on a combination of a code rate and a modulation order. The smaller the code rate or the larger the modulation order, the larger RX TX power than the TX power of UL data can be configured. In the second embodiment, DCI for scheduling PUSCH may indicate a TX power difference between RS and UL data, or may include a parameter capable of calculating the TX power difference. In a third embodiment, the TX power difference between UCI and UL data may be determined based on a combination of data code rate and UCI code rate. The smaller the data code rate is than the UCI code rate, the larger the UCI TX power can be configured. In the fourth embodiment, DCI for scheduling PUSCH may indicate a TX power difference between UCI and UL data, or may include a parameter capable of calculating the TX power difference.

Now, power control based on an access band of a wireless device is described.

The NR system may be configured such that the BS covers a wide system frequency band and the wireless device operates in only a portion of the system frequency band. A portion of the band is called a band portion or bandwidth portion (BWP). The BS may transmit a Broadcast Channel (BCH) in each of the plurality of BWPs within the system band, the broadcast channel carrying the DL synchronization signal and the system information. Even the BWP in which the synchronization signal is transmitted may not provide all system information required for the wireless device to access the BS. For convenience, BWP is referred to as inaccessible BWP. The BWP in which the synchronization signal and all system information are transmitted may be referred to as an accessible BWP. The wireless device may obtain DL synchronization through the accessible BWP and thereafter may read the remaining system information by moving a band to the accessible BWP according to the system information on the BCH of the inaccessible BWP and may establish a connection with the BS.

An additional physical cell ID is not allocated to BWP and BWP can be dynamically switched through DCI so that DL/UL communication can be performed only in one BWP at a time. The technical reason for introducing multiple BWPs in one cell is that data is scheduled by different BWPs according to the service required at each time instant by allowing different sets of parameters (e.g., subcarrier spacing, OFDM symbol length, etc.), HARQ delay, power control, etc. to be configured for each service of a wireless device. In addition, the BS may configure a plurality of BWPs having different bandwidths to the wireless devices and communicate with the wireless devices at various BWPs according to traffic, thereby improving power saving and frequency efficiency. It is also possible to consider the use of configuring different beams for each BWP and naturally switching the beams by switching the BWP.

UL power control may be applied independently for each BWP. Independent UL power control parameters may be configured for each BWP and independent closed loop UL power control may be applied.

For each BWP, it may be desirable to adjust the amount of interference affecting neighboring cells or to adjust the quality target for receiving the UL signal. The BS may configure UL power control parameters for each BWP. The UL power control parameters may include a TX power offset value and an allowed maximum TX power P for each physical channel (e.g., PUSCH, PUCCH, SRS)_CMAXAt least one of (a). The information about the UL power control parameters may be broadcast or may be transmitted through device-specific signaling.

A default UL power control parameter value may be configured for a default BWP and parameter values may be configured in the form of an offset of the default UL power control parameter for the remaining BWPs. Alternatively, default UL power control parameters may be configured regardless of BWP, and parameter values may be configured in the form of an offset to the default UL power control parameters for the remaining BWPs.

To compensate for fast fading between BWPs, the BS may send independent closed-loop power control commands for each BWP. Thus, the wireless device may adjust the independent TX power for each BWP.

P can be configured independently for each BWP_CMAX. The wireless device may report the PH and P of each BWP_CMAX. The wireless device canReporting default PH and default P for default BWP_CMAXAnd may report PH and P for the remaining BWPs_CMAXThe offset value of (2).

Multiple serving cells (or multiple carriers) may be configured for a wireless device and each serving cell may provide multiple BWPs. In transmission period q, P may be transmitted_CMAX,cIs provided to the serving cell and can provide P_CMAX,c,iIs provided to BWP i in the serving cell c. In transmission period q, the UL TX power of the wireless device is adjusted to not exceed P_CMAX,c,iAnd is adjusted such that the total UL TX power of BWPs in the serving cell c does not exceed P_CMAX,c. The wireless device can simultaneously adjust the total TX power in all serving cells to not exceed P_CMAX,total。P_CMAX,totalMay be configured by the BS or may be defined by the maximum TX power capability of the wireless device.

The total TX power of the plurality of UL channels to be simultaneously transmitted in the plurality of BWPs may be considered to use a lower TX power in any one of the plurality of UL channels according to priority or to drop any one transmission among the plurality of UL channels. A priority may be assigned to each BWP. The wireless device may preferentially reduce TX power of the UL channel in BWP not in BWP with higher priority but in BWP with lower priority, or may drop the transmission. The priority may be specified by the BS through RRS signaling or the like, or may be defined according to the properties of BWP (e.g., bandwidth, subcarrier spacing, symbol duration, etc.).

Pl (i) is a parameter for calculating PH and UL TX power by using DL path loss estimation values calculated by the wireless device, as shown in equation 1 and equation 2. When a wireless device performs UL transmission over BWP, the DL path loss may be measured to determine UL path loss compensation to the BS, which may be assumed to be equivalent to the UL path loss. The wireless device may measure DL Reference Signal Received Power (RSRP) through the synchronization signal or RS sent through the reference BWP and may compare the measured DL RSRP to the TX power of the synchronization signal/RS to measure DL path loss. A reference BWP for measuring DL path loss among a plurality of BWPs configured to a wireless device may be measured as follows.

(i) The BS may specify the reference BWP through RRC signaling.

(ii) One of the BWPs assigned to the wireless device for data transmission may be designated by the wireless device as a reference BWP.

(iii) When allocating a non-accessible BWP for data communication, the wireless device may designate the accessible BWP as a reference BWP. The accessible BWP may be designated by the BS or may be determined by a predetermined rule. For example, an accessible BWP closest to the inaccessible BWP may be specified.

The reference for measuring DL path loss may be specified independently of BWP for data communication. The reference BWP may mean a band or a center frequency for transmitting a synchronization signal or RS that may be used in DL path loss measurement.

Fig. 9 illustrates a TX power control method according to an embodiment of the present disclosure.

In step S910, the wireless device receives a Transmit Power Command (TPC) for adjusting the TX power of the UL channel (PUSCH/PUCCH/SRS). In step S920, the wireless device controls UL TX power by applying the received TPC.

TPC may be included in the DCI for scheduling UL channels or TPC-specific DCI for transmission of multiple wireless devices (or multiple UL channels). The DCI may further include a delay field related to transmission timing of actually transmitting the UL channel.

Fig. 10 shows an example of UL channel scheduling with a delay field. After receiving the scheduling DCI at slot n, the scheduled UL channel is transmitted at slot n + K. The delay field in the DCI includes information indicating K. K may indicate only the minimum delay at which the UL channel can be transmitted, and the UL channel may not necessarily be transmitted at time slot n + K. The slot-based K is for exemplary purposes only, and a subframe-based or OFDM symbol-based or sub-slot-based K is also possible.

Fig. 11 shows an example of UL feedback with a delay field. DCI received at time slot n triggers PDSCH reception at time slot n + K1. At slot n + K1+ K, HARQ feedback (e.g., ACK/NACK) corresponding to the PDSCH is triggered. The delay field in the DCI for slot n may include information about K. K only indicates the minimum delay at which feedback can be sent, and feedback may not necessarily be sent at time slot n + K. The slot-based K is for exemplary purposes only, and a subframe-based or OFDM symbol-based or sub-slot-based K is also possible.

In one embodiment, it is assumed that the value K defined by the delay field is in the range from Kmin to Kmax. If the wireless device receives DCI with TPC at slot n, TPC may be applied from slot n + Kmin or slot n + Kmax. Upon receiving DCI with TPC at slot n, TPC may be applied from slot n + K (Kmin ≦ K ≦ Kmax) or after slot n + K. The DCI may additionally include a delay field or may include only the TPC. If multiple delay fields are given, TPC may be applied from the minimum or maximum of the multiple values K. If a plurality of delay fields are given, TPC can be applied from "minimum + offset" or "maximum + offset" among the values K. The offset may be greater than or equal to 1.

In another embodiment, TPC may be applied from slot n + Knm1 once DCI is received at slot n. Knm1 may be a fixed value. n + Knm1 may be a value common to all wireless devices in the cell, or may be a value given to each wireless device. This operation can be applied only when the DCI does not include the delay field.

In another embodiment, TPC may be applied from slot n + Knm2 once DCI with TPC is received at slot n. Knm2 may be a value given according to the capabilities of the wireless device. The Knm2 may be a value corresponding to a minimum time or a maximum time that a scheduled UL channel can be transmitted from a slot receiving DCI according to the capability of a wireless device. Knm2 may be "minimum time + offset" or "maximum time + offset". The offset may be greater than or equal to 1. This operation can be applied only when the DCI does not include the delay field.

In the above proposal, the values K, Kmin, Kmax, Knm1, and Knm2 may be expressed in any time unit such as an OFDM symbol unit or a slot unit. The timing n for receiving the PDCCH (or PDSCH) may also be expressed not in a slot unit but in any time unit, and may be, for example, the last OFDM symbol in which the PDCCH (or PDSCH) is received.

Now, a DCI format for TPC transmission is proposed.

Multiple independent closed loop power control (CL-PC) procedures may be configured to apply independent power control for PUSCH/PUCC/SRS transmissions on different beams or different services, etc. Further, a group TPC DCI may be defined to transmit a TPC for one or more wireless devices.

It is assumed that the TPC for one CL-PC procedure has m bits and the payload of the group TPC DCI has N x m bits. Thus, a group TPC DCI has N TPC fields. The BS may inform the wireless device of the location of the TPC field having the TPC for the wireless device among the N TPC fields through RRC signaling or the like.

Assume that the TPC field of the hybrid TPC for multiple CL-PC processes has n bits (n > ═ m). For example, the hybrid TPC may include information of a TPC or CL-PC process to which the TPC is applied. If n is a multiple of m, the hybrid TPC for each CL-PC process may be expressed by a number of m-bit TPC fields. That is, assume that m is 2 and n is 4. If the group TPC DCI payload consists of 20 bits, 10 TPC fields in the group TPC DCI may be grouped into 5 groups, and thus each group may represent a mixed TPC. The location of the TPC field for each of the plurality of CL-PC processes may be reported to a wireless device having the plurality of CL-PC processes. Alternatively, the location of the TPC field of a first of the plurality of CL-PC processes may be reported and the TPC for the remaining CL-PC processes may be obtained from consecutive TPC fields. For example, assume that four CL-PC processes are assigned to the wireless device and the location of the assigned TPC field corresponds to index 3. The wireless device may identify that four TPC fields consecutive from the TPC field with index 3 represent the TPC for the four CL-PC processes.

Fig. 12 illustrates a problem caused by using the existing TPC.

If n is not a multiple of m, it is difficult to report the TPC field to a wireless device that configures multiple CL-PC processes based on the m-bit TPC field. For example, it is assumed that one TPC field consists of 2 bits (m ═ 2) and a hybrid TPC consists of 3 bits (n ═ 3), including 1-bit CL-PC process ID and 2-bit TPC. The position of the 3-bit TPC field cannot be correctly reported using the index of the existing 2-bit TPC field.

In an embodiment, if n is not a multiple of m, the location of the hybrid TPC is not based on the location of the m-bit TPC field. In contrast, the position of the hybrid TPC in the DCI format is expressed by a bit index. In the example of fig. 12, the positions of the fields of the second and third bits may be expressed by a bit index 3. Alternatively, when the n-bit TPC field and the m-bit TPC field may be combined in an arbitrary order within the DCI, the position of the m-bit TPC field may be reported based on the bit index.

Fig. 13 shows an example of a proposed group TPC DCI.

If n is not a multiple of m, the position of the n-bit TPC field may be expressed by the index of the m-bit TPC field and the bit shift value. It is assumed that the group TPC DCI has 8 2-bit TPC fields and has field indices of 0 to 7. The position of the 3-bit TPC field may be expressed by an index of the 2-bit TPC field and a k-bit shift. Here, 0 ≦ k ≦ n-m. Alternatively, the location of the m-bit TPC field may be reported based on the bit index when the n-bit TPC field and the m-bit TPC field may be combined in any order within the DCI.

Fig. 14 shows another example of a proposed group TPC DCI.

If n is not a multiple of m, the starting position of m bits in the n-bit TPC field may be reported based on the index of the m-bit TPC field and the position of the remaining (n-m) bits may be determined by the combination of the DCI payload size P and the corresponding 2-bit TPC field index. For example, the position of a 2-bit TPC field index may be reported for a 3-bit TPC field, and the remaining 1 bit may be expressed by the (16-K) -th bit. In general, the positions of the remaining (n-m) bits may be identified based on the P-K x (n-m) th bits, and P may indicate a size in the payload of the DCI format that does not include padding bits.

Fig. 15 shows another example of the proposed group TPC DCI.

If n is not a multiple of m, a start position of the n-bit TPC field is reported as an n-bit TPC bit index, and the n-bit TPC field index is determined as a relative position with respect to a last position according to the DCI payload size P. For example, when the indexes of five 3-bit TPC fields are 0 to 4, a 3-bit TPC field index may be defined in a direction opposite to the last bit of a 16-bit DCI payload (i.e., a direction opposite to the direction in which a 2-bit TPC field index is given). In contrast, the m-bit TPC field index may start from the last bit, and the n-bit TPC field index may start from the first bit. In this case, the TPC payload may mean a size other than the padding bits. P may indicate a size other than padding bits of a payload of the DCI format.

Fig. 16 shows an example of timing applied after receiving the TPC DCI.

Upon receiving a TPC DCI (or set TPC DCI) with a TPC at slot n, the wireless device may apply TPC at slot n + K1+ K2. In one embodiment, K1 may be a fixed value. K1 may be a value common to all wireless devices in the cell or may be a value given to each wireless device. In another embodiment, K1 may be a value given according to the capabilities of the wireless device. K1 may be a value corresponding to the minimum time or the maximum time that TPC can be applied from the slot in which TPC DCI is received according to the capability of the wireless device. K2 is an offset value and may be 0, 1, or higher. The values K1 and K2 may be expressed in any time unit such as an OFDM symbol unit or a slot unit. The timing n for receiving the PDCCH carrying the TPC DCI may also be expressed not in a slot unit but in any time unit, and may be, for example, the last OFDM symbol of the received PDCCH.

Now, a scheme of testing and controlling UL TX power will be described.

When BF is performed using a plurality of antenna arrays in a high frequency band above 24GHz, it may be difficult to measure the TX power of a wireless device between a power amplifier and an antenna connector if one antenna array contains many antenna elements with high density. Therefore, in order to test whether UL power control is correctly performed, it may be easier to measure TX power directly output from the air through an antenna.

The wireless device receives the DL signal transmitted by the BS through an RX beam having a direction and directional gain formed by the wireless device. The wireless device measures the RX power of the DL signal and measures the path loss from the BS. It is assumed that the measured path loss is compensated while transmitting the UL signal to the BS through the TX beams having the same or similar direction and directional gain. The measured path loss PL may include a path loss component L in the air and an antenna gain component D caused by the RX beam, and may be defined as PL-L-D _ dl. Because it is difficult for the wireless device to separate only component L, the path loss compensation component in TX power is- (L-D dl). If the TX antenna directional gain component D ul is added, -L + D dl + D ul is added to the TX power. If D _ dl is D _ ul, the result is-L +2D _ dl, which leads to a problem that the antenna gain is considered twice. Therefore, to correctly compensate for the path loss, UL power control is applied to the TX power at the antenna connector, rather than the transmitter isotropic radio power (EIRP) measured over the air. The TX power measured at the antenna connector is called the Transmit Radio Power (TRP).

Therefore, when applying UL power control based on TRP of a wireless device, a scheme of testing TRP and power control may be performed as follows. The scheme may be equally applied to TRP testing of a BS or other wireless node.

The antenna gain Di is obtained for the beam shape and beam direction formed by the wireless device. i is an index indicating the beam shape and beam direction. First, to test whether the TRP required for beam i output or whether the TRP does not exceed a defined maximum TRP, the EIRP of beam i is measured OTA. The TRP of beam i can be expressed in EIRP-Di or EIRP-Di + -e. e is a value that takes fault tolerance into account. Therefore, in the test of TX power, it can be tested whether TRP satisfies the TX power requirement by assuming TRP as a value obtained by subtracting the estimated value Di (+ -e) from the EIRP measurement value. The test may be performed for a plurality of predetermined beams i. In order to practically perform UL power control on TRP, the value Di may be reported to the BS in advance. The BS can refer to and configure a target value of the TRP or the like with the value Di. The value of Di may be an absolute value or an offset value of the antenna gain for a particular beam. In addition, the scheme can also be equally applied to TRP test of BS or other wireless nodes.

Fig. 17 is a block diagram illustrating a wireless communication system implementing an embodiment of the present disclosure.

Wireless device 50 includes a processor 51, a memory 52, and a transceiver 53. The memory 52 is coupled to the processor 51 and stores various instructions executed by the processor 51. The transceiver 53 is coupled to the processor 51 and transmits and/or receives radio signals. The processor 51 implements the proposed functions, procedures and/or methods. In the foregoing embodiments, the operation of the wireless device may be implemented by the processor 51. When the foregoing embodiments are implemented using software instructions, the instructions may be stored in the memory 52 and executed by the processor 51 to perform the operations described above.

The BS 60 includes a processor 61, a memory 62, and a transceiver 63. The BS 60 may operate in an unlicensed frequency band. The memory 62 is coupled to the processor 61 and stores various instructions executed by the processor 61. The transceiver 63 is coupled to the processor 61 and transmits and/or receives radio signals. The processor 61 implements the proposed functions, procedures and/or methods. In the foregoing embodiment, the operation of the BS may be implemented by the processor 61.

The processor may include an Application Specific Integrated Circuit (ASIC), other chipset, logic circuit, and/or data processor. The memory may include Read Only Memory (ROM), Random Access Memory (RAM), flash memory, memory cards, storage media, and/or other storage devices. The transceiver may include baseband circuitry for processing radio signals. When the above-described embodiments are implemented in software, the above-described scheme can be implemented using a module (process or function) that performs the above-described functions. The module may be stored in the memory and executed by the processor. The memory may be disposed internal or external to the processor and connected to the processor using various well-known means.

In the above exemplary system, although the method has been described based on a flowchart using a series of steps or blocks, the present disclosure is not limited to the order of the steps, and some steps may be performed in a different order from the rest of the steps or simultaneously with the rest of the steps. Further, those skilled in the art will appreciate that the steps shown in the flowcharts are not exclusive and may include other steps or one or more steps in the flowcharts may be deleted without affecting the scope of the present disclosure.

Claims (6)

1. A method for reporting power headroom in a wireless communication system, the method performed by a wireless device comprising:

receiving first Downlink Control Information (DCI) for scheduling a first Physical Uplink Shared Channel (PUSCH) transmission in a first slot on a first bandwidth part (BWP) of a first serving cell;

receiving second DCI for scheduling a second PUSCH transmission in a second slot on a second BWP of a second serving cell;

receiving third DCI for scheduling a PUSCH transmission of a third serving cell;

calculating a first power headroom for a PUSCH transmission in a first slot on the first BWP of the first serving cell;

based on the first time slot at least partially overlapping with each of a plurality of time slots on the second BWP of the second serving cell, wherein the first BWP of the first serving cell has a first sub-carrier spacing (SCS) that is less than a second SCS of the second BWP of the second serving cell such that a duration of each time slot on the first BWP is longer than a duration of each time slot on the second BWP:

calculating a second PH for PUSCH transmission in the second slot on the second BWP of the second serving cell, wherein the second slot is an initial slot of a plurality of slots that completely overlaps in time with the first slot; and

reporting the first PH and the second PH,

wherein the first DCI includes a Transmit Power Command (TPC) to be applied to the PUSCH transmission in a first slot on the first BWP of the first serving cell and a delay field related to a delay between a slot in which the first DCI is received and the first slot in the PUSCH transmission performed on the first BWP of the first serving cell, and

wherein the first PH of the PUSCH transmission for the first serving cell is calculated based on the PUSCH transmission for the first serving cell overlapping in time with a PUSCH transmission for a third serving cell, without considering the PUSCH transmission for the third serving cell, and the third DCI is received after the first DCI.

2. The method of claim 1, wherein the first SCS of the first BWP for the first serving cell is equal to a first value of 15KHz, 30KHz, 60KHz, and 120KHz, and

wherein a second SCS of the second BWP of the second serving cell is equal to a second value greater than the first value among 15KHz, 30KHz, 60KHz, and 120 KHz.

3. The method of claim 2, wherein each slot on the first BWP and each slot on the second BWP comprises 14 orthogonal frequency division multiplexing, OFDM, symbols,

wherein a duration of each OFDM symbol on the first BWP is different from a duration of each OFDM symbol on the second BWP.

4. An apparatus for a wireless communication system, the apparatus comprising:

a transceiver configured to transmit and receive radio signals; and

a processor operably coupled to the transceiver and configured to:

control the transceiver to receive first Downlink Control Information (DCI) for scheduling a first Physical Uplink Shared Channel (PUSCH) transmission in a first slot of a first bandwidth part (BWP) of a first serving cell;

control the transceiver to receive second DCI for scheduling a second PUSCH transmission in a second slot of a second BWP of a second serving cell;

control the transceiver to receive third DCI for scheduling a PUSCH transmission of a third serving cell;

calculating a first power headroom for a PUSCH transmission in a first slot on the first BWP of the first serving cell;

based on the first time slot at least partially overlapping with each of a plurality of time slots on the second BWP of the second serving cell, wherein the first BWP of the first serving cell has a first sub-carrier spacing (SCS) that is less than a second SCS of the second BWP of the second serving cell such that a duration of each time slot on the first BWP is longer than a duration of each time slot on the second BWP:

calculating a second PH for PUSCH transmission in the second slot on the second BWP of the second serving cell, wherein the second slot is an initial slot of a plurality of slots that completely overlaps in time with the first slot; and

controlling the transceiver to report a first PH and the second PH,

wherein the first DCI includes a Transmit Power Command (TPC) to be applied to the PUSCH transmission in a first slot on the first BWP of the first serving cell and a delay field related to a delay between a slot in which the first DCI is received and the first slot in the PUSCH transmission performed on the first BWP of the first serving cell, and

wherein the first PH of the PUSCH transmission for the first serving cell is calculated based on the PUSCH transmission for the first serving cell overlapping in time with a PUSCH transmission for a third serving cell, without considering the PUSCH transmission for the third serving cell, and the third DCI is received after the first DCI.

5. The apparatus of claim 4, wherein the first SCS of the first BWP of the first serving cell is equal to a first value of 15KHz, 30KHz, 60KHz, and 120KHz, and

wherein a second SCS of the second BWP of the second serving cell is equal to a second value greater than the first value among 15KHz, 30KHz, 60KHz, and 120 KHz.

6. The apparatus of claim 5, wherein each slot on the first BWP and each slot on the second BWP comprises 14 Orthogonal Frequency Division Multiplexing (OFDM) symbols,

wherein a duration of each OFDM symbol on the first BWP is different from a duration of each OFDM symbol on the second BWP.

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